A project being analyzed by PERT has 60 activities, 13 of which are on the critical path. If the estimated time along the critical path is 214 days with a project variance of 100, the probability that the project will take 224 days or more to complete is
A) near zero
B) 0.0126
C) 0.1587
D) 0.8413
E) 2.14

Question

Quizplus · Accepted Answer

First, we need to calculate the standard deviation of the critical path, which would be the square root of the project variance, i.e. square root of 100 = 10.

Next, we can calculate the z-score for the probability of completing the project in 224 days, using the formula:

z = (x - mean) / standard deviation

where x is the number of days, mean is the estimated time along the critical path (214 days), and standard deviation is 10.

z = (224 - 214) / 10 = 1

Using a standard normal distribution table or calculator, we can find the probability of z being greater than 1, which is approximately 0.1587.

Therefore, the probability that the project will take 224 days or more to complete is 0.1587, or about 16%. The best choice is C.

A Project Being Analyzed by PERT Has 60 Activities, 13